1. Field of the Invention
The invention generally relates to a mix formulation for the production of edible, biodegradable, and compostable food packaging and service items and methods for use of said formulations.
2. Background
Conventional disposable food service items are commonly made from paper or paperboard (commonly coated or impregnated with a polymeric water-proofing material such as wax or polyethylene), or one of a variety of plastics (polystyrene is the most common). In addition, ovenable disposables are made from aluminum or CPET, commonly known as dual ovenable plastic.
During the introduction of Biosphere biodegradable compostable products, it was found that children often expressed a desire to eat the articles presented. When asked, adults also expressed an interest in edible packaging or food-service items. Edible, starch-based food service items which were greeted with considerable public enthusiasm at the 1994 Winter Olympic Games in Lillehammer, Norway; after use, those items were fed to livestock, eliminating a large source of waste. Home and industrial bakers have expressed a desire for edible molding devices for cakes, cupcakes, muffins, tarts, pies, and the like, to replace the metal and paper items currently in use.
In addition to the intrinsic appeal of edible packaging materials to children and other consumers, there is a growing recognition that the environmental costs of using “cheap” plastic materials for packaging may be quite high. The expected lifetime of a polystyrene cup, for example, is about 500 years, and each American disposes an average of about 100 cups per year. Polystyrene is made by chemical processing of benzene and ethylene, both byproducts of the petroleum industry, and thus both nonrenewable resources. Although the environmental record of the petroleum industry has improved greatly since the mid-twentieth century, extraction and processing of petroleum for fuel and chemical production remain recognized environmental problems. Questions have also been raised about the wisdom of using a limited natural resource (fossil hydrocarbon stocks) to produce disposable items (which exacerbate waste handling problems) rather than reserving the resource for production of durable goods.
United States Government sources indicate that packaging (of all types) makes up 32 percent of the municipal solid waste stream by weight. Food packaging makes up about 9 percent of the waste stream. Costs of disposal of municipal wastes are likely to increase as landfill regulations become more stringent, current sites are filled and replaced by (usually) more distant sites, and waste transportation costs increase (along with fuel costs).
Pet food packaging also contributes appreciably to the waste stream. The total annual worldwide market for pet food packaging has been estimated to exceed $500 million, with increasing emphasis on smaller packaging, including portion-sized packages. As in all industries, the smaller the quantity of product per unit sold, the greater the ratio of packaging volume to product volume; the quantity of pet food packaging being used is thus growing at a higher rate than the quantity of pet food itself.
Materials that are impervious to moisture and impermeable to oxygen and other gases include conventional plastics, metals, glass, and plastic-coated paper or paperboard. Of these, metal, glass, paperboard, and molded plastics typically provide structural protection of the packaged items as well as barrier properties, whereas plastic films and plastic-coated papers mainly provide barrier protection rather than structural protection. Typically much more mass is required to obtain the structural rigidity required of packaging than is required to obtain suitable barrier properties alone. None of these materials are biodegradable or compostable. To the extent that they enter the disposal waste stream (i.e., that they are not recycled), these materials are persistent; they will remain in landfills even where oxygen and moisture are provided to encourage biodegradation.
In addition to waste disposal concerns, some current research suggests that certain chemicals (phthalates and other plasticizers) used in the manufacture of plastics may have detrimental effects on the environment and on human reproductive systems, even at extremely low concentrations, by affecting the endocrine (hormone) system in humans and many other animal species. The observations suggest that, in both wildlife and humans, very low concentrations of these compounds can mimic or interfere with hormones that play important roles in embryonic development, resulting in effects such as hermaphroditism in gastropods; feminization of fish, alligators, and some mammals; malformations or morbidity in amphibians, fish, and birds; and various effects in human developmental and reproductive biology. Although the research and many of the conclusions that have been drawn from it are controversial, the FDA and some Japanese and European regulatory agencies are considering bans or additional regulations on certain phthalates. Regardless of how this debate is resolved in the future, there is currently increasing public concern about the safety of plastics and the plasticizers that are used to improve their physical properties.
The desire to use disposable packaging materials that are biodegradable and compostable has been steadily increasing in the last decade. As recently as March, 2003, Taiwan outlawed the use of polystyrene foam in disposable packaging. China's major cities (e.g., Beijing and Shanghai) have also outlawed the use of polystyrene foam in disposable packaging. Commenting on solid waste policy in the United States, the web site of American Society of Civil Engineers says that “the problem of over consumption should be addressed, with the goal of reducing the production and consumption of unnecessary goods, packaging and throwaways. Toxic materials used in products and packaging and produced as byproducts in production processes should be minimized.”
Unlike plastics, paper and paperboard are made from wood pulp, which is a renewable material. The regeneration time, however, for wood fiber—the time required to grow a tree—is substantial, and the chemical processing needed to produce white (“bleached”) fibers has been recognized to be detrimental to the environment. The use of unbleached and recycled fibers helps alleviate these environmentally detrimental activities, but the use of slow-growing trees as a fiber source when many agricultural byproduct sources are available is in itself questionable.
Further, in the current art, starch-based food service articles typically contain two or three major phases: a matrix material (mainly starch) that contains inorganic filler materials and/or fibrous materials. The mechanical properties of the starch matrix material are critical to the performance of these articles. Baked unmodified starch is typically quite fragile and brittle when dry, but relatively soft and pliable when the starch contains 5% to 10% moisture. In current practice, fiber is often added to the formulation to increase the flexural strength and fracture energy of starch-based items, especially during the period immediately after demolding, when the moisture content of the starch is very low. Even with the addition of significant amounts (10% or more) of fiber, however, starch-based articles are commonly very brittle immediately after demolding or when stored for extended periods in dry environments (heated buildings in winter, air conditioned buildings in summer, desert environments any time of year). Brittle failure of starch-based articles thus continues to present problems during the manufacturing process (especially before coatings or laminated films are applied) and when the articles are used in dry environments.
Moreover, in the current art, inorganic mineral fillers (e.g., calcium carbonate, silica, calcium sulfate, calcium sulfate hydrate, magnesium silicate, micaceous minerals, clay minerals, titanium dioxide) are often included in formulations used to produce starch-based biodegradable food service articles. These fillers are not, however, biodegradable. Marketing claims made for products using these materials as fillers point out that the materials are natural, renewable, and environmentally benign. However, there are inherent environmental costs associated with the mining (or synthesis) and processing of all inorganic filler materials.
Finally, in the current art, the most commonly used fiber in starch-based food service articles is wood-pulp fiber (similar to the paper based articles). As the main source material for the paper industry, it is readily available, is consistent in quality and material properties, and has the main properties needed to serve as structural elements in the finished food service articles. The use, however, of slow-growing trees as a fiber source when many agricultural byproduct sources are available is, as set forth above, in itself questionable.
Accordingly, there is a need for an improved system for producing edible, biodegradable, and compostable disposable items that can serve the full range of uses to which containers, plates, trays, and bowls are usually put. Consumers clearly would benefit from the introduction of a new edible food service and packaging material. Society at large would clearly benefit from an overall reduction in the amount of food packaging materials in the municipal solid waste stream.
Further, there is a need to reduce the proportion of persistent, non-biodegradable food packaging in the municipal waste stream. Development of packaging systems that combine edible, compostable, and biodegradable materials for structural rigidity with minimal amounts of plastic film or plastic-coated paper for protection from water, water vapor, oxygen, and contaminants would be beneficial.
Further, development of packaging materials made entirely from natural, edible ingredients would reduce both environmental and human health effects of plasticizers, to whatever extent they are eventually shown to occur. Until the debate over the issue is resolved, edible packaging materials may serve as an alternative to plastics for concerned consumers.
There is also a need for an improvement in the current art that will replace mineral fillers with fully biodegradable and renewable plant-based organic materials that serve the same role as traditional mineral fillers. Even greater benefit is available if the filler material is currently produced as a byproduct of the production of another agricultural material.
Finally, there is also a need for methods and formulations that incorporate fibrous materials from annually grown non-wood plants, and particularly from materials that are byproducts of commodities already in production.